Figure 4.

Accumulation and distribution of nanoparticles in tumor tissue 12 h after i.v. injection into B16-F10 tumor-bearing mice. C57BL/6 mice (female, 6–8 weeks, n = 3) were s.c. injected with B16-F10 tumor cells (5 × 10⁵). When tumors reached 6–8 mm in diameter, mice were i.v. injected with AS-M-NP. As controls, mice were also i.v. injected with AI-M-NP, AS-NP, NP, and sterile PBS. Mice were euthanized 12 h later to collect tumor tissues, which were cryosectioned, stained with PE-labeled rat anti-mouse CD68 antibody and then examined under a fluorescence microscope to localize the FITC-labeled nanoparticles (green) and macrophages (red). White arrow heads indicate the colocalization of the nanoparticles with TAMs. (Inset in AS-M-NP: representative colocalization of the nanoparticles with TAMs shown at a higher magnification). Micrographs shown are representative images from 3 slides per mouse (bar = 200 μm).